Motor assembly with magnetic brake



@y l, 1950 J, E, CHAPMAN 2,514,693

MTOR ASSEMBLY WITH MAGNETIC BRAKE Filed June 2l, 1944 2 Sheets-Sheet l5r. Illllltlllll INVENTOR. 24 "35 JAMES si. CHAPMAN My M, 1959 J. E.CHAPMAN 2,5%693 MOTOR ASSEMBLY WITH MAGNETIC BRAKE Filed June 2, 1944 2Sheets-Sweat 2 INVENTOR Patented July 11, 1950 2,514,893 MOTOR. ASSEMBLYWITH MAGNETIC BRAKE James E. Chapman, Phoenix, Arix., assigner to TheGarrett Corporation,

Los Angeles, Calif., a

corporation of California Application June 21, 1944, Serial No. 541,31214 Claims. (CL 172-36) This invention relates to motors and, while theinvention is applicable to motors of any size, it is expected to haveits greatest utility when applied in the construction of relativelysmall electric motors.

When it is necessary to take apart a small motor as ordinarilyconstructed it becomes necessary to remove many screws or bolts andsometimes soldered wires must be broken away at soldered points. Thereassembling of such a motor is also accomplished with dimculty.

One of the objects of this invention is to provide a motor of simpleconstruction which can be very easily assembled and taken apart withoutnecessitating the removal of a great number of fastening screws or boltsand without breaking apart any soldered connections. This is veryadvantageous because in many situations where such motors areemployed-for example, on airplanes it may be necessary to effect repairsat a point remote from repair shops and where the repairing must beeffected without having a mechanic available; and often without havingat hand any special tools suitable for such repair work.

Another object of the invention is to produce a motor, the casing ofwhich is divided into one or more sections, each section carrying someof the working parts of the motor to which access can be had readilyafter the sections have been separated from each other; also to providesuch a construction with parts having features which will enable themotor circuit to be established automatically, as it were, when thesections of the casing are put together.

Another object oi the invention is to provide an easily assembled motorhaving a casing body and disconnectable caps, each of said caps carryingWorking parts or controlling parts for the motor; and to provide meanswhereby any necessary working circuits will be established through themotor and through the electrical parts in the two caps when the caps areplaced in position when being attached to the casing body.

Another object of the invention is to provide a. well housed motor withimproved means for carrying the brushes that cooperate with thecommutatcr, and to mount the same so that they can be readily removedand replaced from' the outside of the casing and without necessitatingtaking the motor apart.

Another object of the invention is to provide a cap assembly for a motorof this type in which the brushes and the bearing for the motor shaftare carried in a one-piece cap.

Another object of the invention is to provide a cap assembly for a motorof this type which will not only include a bearing for the motor shaft,but which will also carry an electrically controlled brake for the motorand a thermostatic circuit breaker so placed that it will operate tobreak the circuit if the adjacent parts of the motor become too hot forsafety.

Further objects of the invention will appear hereinafter.

The invention consists in the novel parts and combinations of parts tobe described hereinafter, all of which contribute to produce an easyassembling motor.

A preferred embodiment of the invention is described in the followingspecification, while the broad scope of the invention is pointed out inthe appended claims.

In the drawing:

Fig. 1 is a plan of a motor embodying my invention.

Fig. 2 is a longitudinal section through the mctor illustrated in Fig.l, taken about on the line 2 2 of Fig. 1, but illustrating the end capsof the casing separated from the casing body.

Fig. 3 is an elevation showing the inner side oi the left hand capillustrated in Fig. 2. This view il; tagen about in the plane of theline 3 3 of Fig. 4 is a vertical section taken about on the line 4 4 ofFig. 2 through the right hand head as illustrated lnFig. 2; but in thisview a portion of the section is broken away back into the motor toillustrate a pole of the motor and its relation to its winding.

Fig. 5 is a fragmentary section taken about on the line 5 5 of Fig. 3and illustrating a tie-bolt that is carried by the left hand cap. andthis view shows a portion of the tie-bolt and a conductor carriedthereby broken away.

Fig. 6 is a diagrammatic view illustrating the circuit through themotor, at the brake, and through the eld coil and the thermo-sensitivemeiigiber for automatically breaking the motor circu Fig. 7 is a viewsimilar to Fig. 2, with the parts of the motor in assembled position.

Before proceeding to a more detailed description o'f the invention, itshould be stated that in the present specication and drawing theinvention is illustrated as applied to a motor having a casing dividedinto sections. In the present instance there are three of thesesections, including a body member and two end sections or caps. The bodymember is provided on its interior with ield coils and poles, and thearmature and a shaft are constructed so that they can slip into positionaxially to cooperate with the field coils and poles.

The two end caps preferably carry bearings for the ends of the shafts,though this is not essential to the invention. One of the end caps ispreferably provided with an automatic brake apparatus which applies thebrake to stop the rotation of the armature when the motor circuit isbroken, and this cap or cap assembly also preferably includes athermo-sensitive means or device which will operate automatically tobreak the motor ci: cuit if the parts adjacent to the thermosensitivemember become overheated.

The cap at the other end of the motor where the commutator for thearmature is located also constitutes a cap assembly in which the brushesare mounted which cooperate with the commutator, and slide intooperative relation to the commutator when this cap assembly is slidintoposition axially to seat on it the adjacent end of the casing body. Inaccordance with this invention, also, when these caps are slid intoposition on the ends of the casing body, the motor circuit isautomatically established through the motor; but of course this motorcircuit is controlled by the usual switch on the exterior of the motor.

This cap assembly, which includes the brushes. is preferably constructedso that the brushes can be withdrawn and replaced without removing thecap. In other words, my invention provides for removal and replacementof brushes for a motor through the casing wall of the motor; and this istrue, regardless of whether the brushes are mounted in a cap assembly asin the present instance or whether the brushes are mounted in a portionof the casting.

In the present instance I construct the motor of three sectionsincluding a casing body la, a disconnectable head or cap Ib, llocated atone end of the body, and a disconnectable head casing or cap Ic at theother end.

In the present instance the body la is of tubular form and within it,.at two diametrically opposite points, are mounted two poles, such asthe pole 2 shown in section in Fig. 4. These poles are attached in anysuitable manner diametrically opposite each other, preferably bycountersunk machine screws inserted from the outer side of the body.

The armature 4 is rigidly mountedvon a shaft 5 which extends all the`way through it, the left end of the shaft having a grooved neck 6enabling the motor to be coupled up to a. driven shaft. In thismotorillustrated, which is a. direct current motor, the other end of theshaft 5 is provided with a commutator 1, the bars of which are connected to the coils 8 of the armature winding.

The end of the armature, remote from the commutator, is provided with arigid brake member 9 which may have a brake lining or facing lll ofsuitable brake material.

The head or cap Ib adjacent this brake member 9 is preferably providedwith an electrically controlled brake member I I, which is in the formof a disc mounted to iioat on the rigid end of the shaft that carriesthe fiuted neck 6. In the present instance, the cap Ib is provided witha brake coil, or solenoid coil, I2, which is located between the hub I3of the head and the annular portion or shell I I. This head or cap Ib isof a magnetic material so that the hub I3 of the cap operates as a corefor-#attracting the brake member il when the coil is energized. In thepresent instance, when the coil I3 is energized, the magnetic attractionholds the brake member Il away from the brake facing I and lets themotor run free, but whenever the coil I2 is de-energized, the brakemember or brake shoe I I is forced by resilient means toward an extremeposition and against the brake lining I8 to exert a braking force on therotor of the motor which, of course, includes the shaft and the armature4.

The resilient means for applying the brake preferably consists of twoarcuate leaf springs (see Figs. 2 and 3) the middle portions of which 4v are attached by bolts located at I6. to diametrically opposite ears orlugs I1 that project outwardly from the body of the brake disc II.

In order to prevent the brake disc or shoe II from rotating, the ends ofthe springs I5 have bent flanges I 8 at their ends which thrust againsta xed part within the cap. In the present instance, they thrust againsttwo tie bolts Isa and ISb which extend longitudinally within the motorand preferably extend all the way through the body I and through theright hand cap Ic.

Associated with the brake and preferably immediately back of it, asillustrated in Fig. 2, l prefer to provide a thermally sensitive memberwhich will open the circuit through the motor if the motor commences tooverheat. For this purpose, I prefer to employ a bimetallic disc 20which is located atvthe end of the coil I2; adjacent its insulation head2l and between this thermostatlc member 20 and the brake shoe Il, Iprovide another insulation head or disc 22.

Other insulation employed consists of a anged sleeve 23 which ts overthe hub I3.

The wiring into the coil I2 is indicated as coming in on a lead wire 24through an opening 25 in the outer shell I 4 of this cap; this lead wireconnectsto a contact 26 on the insulating head 2l, and the thermostat 28has a cooperating contact 21 which will engage the contact 26 when thethermostat and the motor are not overheated. The current fiowing throughthe thermostat passes through two engaging contacts 28 at another point,located respectively on the thermo-A stat 20 and on the insulation disc2|, and the contact on the disc 2| is connected to one end of the coil;the other end of the coil is attached to a contact 28 which is connectedand grounded toouter shell I4 at 30.

The lead-wire or conductor 2| which connects up to the' contact 26 isattached insulatingly alongside of the adjacent tie bolt 19a (see Fig.5). being passed throughvclips 3| that project out from the side of thistie bolt. This tie bolt, like the tie bolt I9b, is preferably securedinthe head Ib by a thread connection 32. Referring again to Fig. 5, atthe other end of this tie bolt ISa. the lead wire 24 has a contact' p in33 which is ollset away from the bolt, as will be described more indetail hereinafter, to enable itl to close a circuit through a contactto one-of the brushes. The bolt ISb is mounted like the bolt I9a, but itdoes not carry any lead wire.

The cap Ic, located at the other end of the motor, is preferably ofmolded material such asa suitable plastic, which is preferably formedoi' an insulating material. This cap has a disc form body and a curvedwall or flange 34 formed with oppositeiy disposed openings 35 throughwhich the two brushes 36 may be inserted from the outside. This isadvantageous for the reason that it avoids the necessity for taking offthe cap when the brushes must be serviced or replaced.

Each brush is guided in a` guide opening 31 formed in a guide block orhousing 38 which is molded into the cap when the same is cast. When thecap is in place on the end of the body Ia, these brushes 35 areyieldably pressed toward the commutator by small coil springs 39 whichthrust against their outer faces. The outer ends of the springs thrustagainst contact discs d0 which iit into the openings 35 and are followedup by insulating discs di. Each brush is connected to its correspondingcontact disc d by a pigtail conductor 42 which has sufficient slack init to insure that the brush will always be able to have sumeientfollow-up" against the commutator as the forward end of the brushbecomes more and more worn away. When the cap lc is slipped intoposition for attachment to the body la. the contact disc of one of thesebrus'hes will alignl with the oii'set contact pin 33 which is carriedonl the tie-bolt lila and this will establish a circuit connectionbetween this brush and the brake coil l2. In order to retain the brushin the brush guide 3l, easily detachable resilient keeper means isemployed. and this preferably consists of a metal yoke 43, the body ofwhich is in the form of a bar that extends diametrically across theopter face of the cap Ic, the ends of the bar being 'provided with bows4/4, terminating in iingrs respectively that seat themselves against theouter faces of the insulation disc 4I.

" The field winding 46 includes two oppositely wound coils 45a and 45h(see Fig. 6), one of which will cooperate in a circuit for driving amotor shaft in one direction and the other of which will cooperate toenable the motor to be driven in a reverse direction. Thelead-conductors or wires 41 and 43 that connect to these two coils i45aand 4Gb can be carried through the motor casingat any suitable point,such as through an .opening provided with a .bushing 49, as illus tratedin Fig. 2. By means of a switch, such as the switch 50 in Fig. 6,`thecircuit can be closed through either of the field coils.

After passing through the field winding, current passes by way of thelead-conductor 4i, Fig. 2, to a contact pin 52 which may be formed as anintegral part of the lead 4 I. This contact pin is located to align withthe contact plate 40 of the brush which is located diametricallyopposite the contact pin 33 that leads from the brushes back to thebrake coil I2. When the cap Ic is shoved up into position, this contactpin 52 slides into position to complete the circuit, in the same manneras the contact pin 33.

The cap ic is provided with a, bearing, preferably a ball bearing, 53,which receives the adjacent end of the shaft 5 of the motor. The housingring 54 for this bearing may be molded into the body of the cap Ic likethe brush guides 38.1 similar ball bearing 55 may be provided for theother end of the shaft 5 and this bearing is of course mounted in thecap Ib.

' In attaching the caps ib and lc to the casing body la, the forwardends of the tie bolts Ita and isb are received in sockets 55 which areenough to project beyond the head lc so that the 'threaded ends canreceive crown nuts 51 which may be seated on the outer face of the capanc? sealed against removal by a sealing vwire 53 passing through smalltransverse holes 59 drilled into the projecting ends of these tie bolts.

Fig. 6 diagrammatically illustrates the wiring arrangement, includingthe thermo-sensitive member 20 which may be 'of Invar metal or a.similar device which will become deformed sufiiciently when overheatedto break the circuit at one or both of the contact points 25 or 28.

It will be evident that a motor constructed as described can be veryreadily taken apart and assembled without the use of special tools andwithout having to disconnect any wires, or break any soldered points.Furthermore, working parts for the motor excepting the field andarmature are carried in the two caps and when the caps are removed, theyare quite accessible for servicing or making replacements.

'I'he fourbosses 8l on the cap l b afford means for mounting the motoron a support for it.

Many other embodiments of this invention may be resorted to withoutdeparting from the spirit of the invention.

I claim as my invention:

l. In an easily assembled motor. the combination of: a casing body openat its ends, having a ileld coll and poles within the same; an armaturehaving a shaft and commutator capable of being slid axially intoposition in the casing body to cooperate with said coil and poles; acasing cap assembly disconnectibly attached to the end of the casingbody adjacent to the commutator, with brushes carried therein to engagethe commutator, said field and said casing head having cooperatingaligning contacts operating to establish the motor circuit through thefield coil and the armature when said casing cap is moved axially ontothe casing body; a second disconnectible casing cap for the other end ofsaid casing body, with a brake and brake coil carried therein; saidsecond disconnectible casing cap having a lead from the brake coilterminating in a contact; and a contact connected with one of saidbrushes and operating to engage the same and connect the brake coil tothat brush when the second disconnectible casing cap is moved axiallyinto position to secure the same to its end of the casing body.

2. In an easily assembled motor having a commutator rotating within thesame, the combination of: a casing member having a wall located adjacentto the commutator, said wall having openings therein to receive brushes;brushes insertable into said openings from outside of said casing, withkeeper means, having a portion extending across the outer face of thewall, for retaining the brushes in their openings.

3. A motor construction according to claim 2 including a brush guideformed integrally in said casing member for guiding each brush towardthe armature; a contact member located at each opening, and having aflexible metallic t connection to its corresponding brush, and means foreiecting circuit connections respectively to said contact members forestablishing a circuit through the armature.

4. In an easily assembled motor having a commutator rotating within thesame, the combination of: a casing member having a wall located adjacentto the commutator, with openings therein to receive brushes; brushesinsertable into said openings from outside of said casing; a contactmember located at each opening, back of its corresponding brush andhaving a iiexible metallic connection to its brush; a spring locatedback of each brush for holding the same yieldingly against the armatureand a contact member insertable in a lateral direction with respect tothe axis of said brush for engaging each contact member to establish acircuit through the brushes and the armature.

5. In an easily assembled motor having a casing body open at its end,the combination of: an armature rotatably mounted within the casing andhaving a commutator located adjacent the open end of the casing body; adetachable cap for the casing body; brush guides mounted in said cap;said cap having openings opposite said brush guides enabling the brushesto be inserted into the same from the outside; contact heads mountedrespectively in said openings metallically connected to the brushes; anda contact member for the motor circuit located in the end of 7 said bodyadjacent said detachable cap operating to slide into contact with one ofsaid contact heads when the cap is applied and seated on the end of thebody by an axial movement, thereby establishing a circuit through thecommutator and the amature.

6. An easily assembled motor according to claim including an insulatingmember mounted in each of said openings, and resilient Ameans forengaging the insulating members on their outer side to hold the same andthe contact heads in lace. p 7. In an easily assembled motor, thecombination of: a casing body open at its ends; a eld winding and polescarried within the body casing: an armature capable of being slidaxially into position to cooperate with said iield and poles, and havinga. shaft projecting at each end from the amature with a commutatorlocated on one end of said shaft and connected with the armaturewinding; a removable head assembly for the casing body disconnectlblyattached to the end adjacent the commutator, with brushes carried in thehead to slide into operative contact with the commutator; said headhaving a bearing for the adjacent end of said shaft; cooperating contactmeans forvthe casing and the head for eiecting connections to saidbrushes, said contact means being separated when the head isdisconnected from the body; and a removable head assembly for the otherend of the said casing, including a casing head with an electric brakemounted therein for the motor; and a bearing for the adjacent end of theshaft, and

contact means for effecting connection of the brake coil with one of thebrushes when the last named head is moved axially into its seatedposition on the adjacent end of the casing.

8. In an easily assembled motor, the combination of: a casing body openat yits ends and a cap disconnectably mounted on one end of said casingbody; electrically actuated means within the cap connected into themotor circuit to cooperate in the operation of the motor; an armaturewithin the casing having a commutator adjacent the other end of thecasing; a disconnectable cap mounted on the other end of said casingbody; brushes carried thereby adapted to slide over the armature whenthe last named cap is moved .in

axially and seated on the casing body; a tie bolt f connected to thefirst named cap extending through the said casing body; a conductor-leadconnected with the said electrical means in the rst named cap andsupported on said tie bolt and having contact means at its end adjacentto the second named cap; said second named cap having contact means toalign with the first named contact means and engage the same when thesecond named cap is being attached to the casing body, and operating toestablish a' circuit through one of the brushes.

9. 'An easily assembled motor according to claim 2 in which insulatingmeans is placed in the openings back of the brushes; and in which thesaid keeper means includes a resilient yoke with a linger adjacent eachendpressing yieldingly on the insulating means to retain the brushes.

l0. In an easily assembled motor having a commutator rotating within thesame, the combination of: a casing member having an open end; a cap forsaid open end, said cap having openings therein to receive brushes;brushes insertable into said openings from the outside of said casing;and a keeper comprising a yoke in the form of a bar extendingdiametrically across the outer face of the cap, said yoke having endsterminating in ngers adapted to be so positioned as to retain thebrushes within said openings.

l1. In an easily assembled motor having a commutator rotating within thesame, the combination of: a casing member having a removable capadjacent the commutator, said cap having openings therein to receivebrushes; and brushes insertable into said openings from outside of thecap, with keeper' means, having a portion extending across the outerface of the cap for retaining the brushes in their openings.

12. In an easily assembled motor having a casing body open at an end andhaving a eld coil and poles in said casing, an armature having acommutator, said armature and commutator being disposed within saidcasing for cooperation with said coil and poles, and brushes engageablewith the commutator, the combination of: a, disconnectable casing capfor said open end of the casing body; a brake and brake coil carried insaid cap; a lead from the brake coil terminating in a contact; and acontact connected with one of the brushes and operating to engage thesame and connect the brake coil to said4 brush when said disconnectablecasing cap is moved intoposition to secure the same to its end of thecasing body. 1,

13. In an easily assembled motor having commutator rotating within thesame, the combination of a casing having a wall located adjacent to thecommutator, said wall having openings therein to receive brushes;brushes insertable into said openings from outside of said casing; meansconnecting the brushes into the'motor circuit; insulating means in theopenings back' of the brushes; and keeper means, having a portionextending across the outer face of the wall, for engaging saidinsulating means and retaining the brushes in their openings.

14. In an easily assembled motor having a casing with a rotor and ashaft, and brushes comprising: a detachable cap for said casing; a brakein said cap; electromagnetic means for controlling said brake, saidbrake being so constructed and arranged as to apply braking force tosaid shaft;l resilient means for normally holding the brake in anoperative position; a heat sensitive member within the cap; meanscooperatin-g therewith for breaking the motor circuit when the part ofthe motor adjacent to the heat sensitive member becomes overheated; andan electrical contact, connected with the electromagnetic means, and soconstructed and arranged as to engage one of the brushes and to beseparated therefrom by detachment of the cap from the casing.

JAMES E. CHAPMAN.

REFERENCES CITED Y The following references are of record in the le ofthis patent:

UNITED STATES PATENTS y Number Name Date 1,751,209 Kucher Mar. 18, 19301,817,597 Zabriskie et al Aug. 4, 1931 1,930,539 Renshaw et al Oct. 17,1933 1,933,628 Kitto Nov. 7, 1933 2,211,006 Doughman Aug. 13, 19402,213,889 Schaeier Sept. 3, 1940 2,214,807 Buckley Sept. 17, 19402,267,114 Lear et al. Dec. 23, 1941 2,348,684 Perkins -..-nu May 9, 194%Certificate of Correction Patent No. 2,514,693 July ll, 1950 JAMES E.CHAPMAN It is hereby certified that error appears in the printedspeoication of the above numbered patent requiring correction asfollows:

Column 3, line 26, for the Word casting read casing;

and that the said Letters Patent should be read as corrected above, sothat the same may conform to the record of the case in the lootent Olce.

Signed and sealed this 24th day of Ootobenn. D. 1950.

[smh] THOMAS F. MURPHY,

Assistant Gommz'ssz'oner of Patents.

